Patient Positioning & Procedures Flashcards

Which radiographic projection best demonstrates the interproximal spaces of the posterior teeth?

Answer: Bitewing

Bitewing radiographs are specifically designed to demonstrate the crowns and interproximal (contact) areas of both upper and lower posterior teeth simultaneously.

For an AP projection of the pelvis, what is the correct positioning of the lower extremities to demonstrate the femoral necks without foreshortening?

Answer: Internally rotate feet 15–20 degrees

Internal rotation of the feet 15–20 degrees places the femoral necks parallel to the image receptor, eliminating foreshortening.

Which projection of the skull best demonstrates the sella turcica in profile?

Answer: Lateral skull

The lateral skull projection places the sella turcica in true lateral profile, making it the best view for evaluating this structure.

Which positioning line is used as a reference for the orbitomeatal line (OML)?

Answer: A line from the outer canthus of the eye to the EAM

The orbitomeatal line (OML) extends from the outer canthus (lateral corner) of the eye to the external auditory meatus (EAM).

For an AP axial projection of the skull (Towne method), the central ray is angled caudally. What is the standard angle when the OML is perpendicular to the IR?

Answer: 30 degrees

The Towne method uses a 30-degree caudal angle when the OML is perpendicular to the IR to project the occipital bone and dorsum sellae.

Which positioning error causes the appearance of an elongated image on a radiograph?

Answer: Insufficient angulation of the central ray

Insufficient central ray angulation (or insufficient part angle) causes the image to appear elongated because the part and film are not properly aligned.